JP2005299799A - Outside joint member of uniform velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an edge shape of the opening of a mouth member which is advantageous in a functional aspect without diminishing a moldability in a cold working such as pressing. <P>SOLUTION: In the outside joint member 1 constructed by coupling the thin-walled mouth member 1a molded by a cold working and a stem 1b, the mouth member 1a is open at the edge and has a plurality of track grooves 6 which are circumferentially arranged and axially extend. Taper portions 8 having a diameter expanded in the direction of the open edge side are arranged between track grooves 6 adjacent to each other. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an outer joint member of a constant velocity universal joint. More specifically, a cup-shaped or cylindrical mouse portion in which inner diameter portions and track groove portions that engage with torque transmitting elements are alternately arranged in the circumferential direction is formed by cold working such as pressing from a plate material or a tube material. The present invention relates to an outer joint member.

  As a conventional technique for manufacturing an outer joint member having a cup-shaped or cylindrical mouse portion in which an inner diameter portion and a track groove portion that engages with a torque transmission element are alternately arranged in the circumferential direction, as an integrated material, The outer joint member is formed by cold forging such as a method of forming by hot forging or hot forging, or a cup-shaped or cylindrical mouse member by cold working such as pressing from a plate material or tube material, and joining with a stem member manufactured separately. There are ways to get it.

  In recent years, the automobile industry has been required to reduce the size and weight of constant velocity universal joints. The outer joint member obtained by the latter cold working meets such needs. In cold working, the cost can be reduced as a whole from the viewpoint of process reduction, tool life extension and rationalization. On the other hand, in the former forming method by warm or hot forging, the forging die is deteriorated by heat, a uniform forging die is required for various product shapes, the forging process and There is a problem in that the manufacturing cost cannot be reduced because the pretreatment and the like are complicated multi-steps.

As a conventional technique, FIG. 4 of Japanese Patent Laid-Open No. 9-76026 discloses a shape having a hook-like portion that curves to the outer peripheral side at the end of the mouse opening. Japanese Patent Application Laid-Open No. 2000-329152 discloses that a flange portion having a substantially circular cross section is formed at an opening end portion of a mouse member. Japanese Patent Application Laid-Open No. 2000-24736 discloses a mouse member that is formed in the same cross-sectional shape toward the opening end without providing a hook-shaped portion or a flange portion.
JP-A-9-76026 (FIG. 4) JP 2000-329152 A (FIG. 1) JP 2000-24736 A (FIG. 4)

  In cold working such as pressing, cracks are likely to occur in parts that give large deformations to the material, so the amount of deformation that can be applied to the material is small compared to warm or hot forging. As a result, the cup-shaped or cylindrical mouse member obtained by cold working such as pressing is thinner in cross section than the cup-shaped mouse part of the outer joint member obtained by warm or hot forging. In addition, the cross-sectional shape has a substantially uniform thickness with a small difference in thickness in the circumferential direction.

  In a mouse member that has been cold worked by a working method such as deep drawing or ironing, distortion due to molding is concentrated particularly at the opening end portion, and cracks due to work hardening are likely to occur. Therefore, the ease of molding is greatly affected by the shape of the open end of the mouse member.

  In order to transmit a larger torque as a constant velocity universal joint, it is necessary to increase the breaking strength against a load applied from the inner joint member to the mouse member. Although the strength can be increased by making the mouse member thick, the ease of forming in cold working is greatly reduced.

  The flange portion in Japanese Patent Laid-Open No. 9-76026 or the flange portion in Japanese Patent Laid-Open No. 2000-329152 functions as an engagement shape with one end of the boot in order to fix the boot for the purpose of sealing the inside of the mouse. However, it is not a part directly related to the torque transmission function as a joint. In addition, since it is difficult to mold the curvature radius of the curved portion as the thickness of the mouse member becomes thicker, the former collar-shaped portion is made of a material such as molding a large collar formed in the pressing process in the subsequent turning process. Cause a decrease in yield. Moreover, since the latter flange part is connected with the mouse | mouth opening edge part, an outer joint member becomes long in an axial direction, and compactness is lost. Therefore, a more advantageous shape is required from the viewpoint of compactness, weight reduction, and material reduction as a joint structure.

  In the case of the conventional technique described in Japanese Patent Laid-Open No. 2000-24736, one end of the boot is fixed by an engagement groove provided on the outer peripheral surface of the opening end of the track groove. In addition, a chamfer part for suppressing interference with the shaft is provided on the inner peripheral part of the opening end part of the small inner diameter part located between the adjacent track groove parts, but the mouse member formed by cold working is Since it is thin, a large chamfer portion cannot be formed to sufficiently prevent interference with the shaft, and the movable range of the joint is restricted. Further, since the chamfer part is partially thin, there is a problem that the strength of the mouse member is lowered.

  An object of the present invention is to provide an opening end shape of a mouse member that is advantageous in terms of function without degrading formability in cold working such as pressing.

  The outer joint member of the constant velocity universal joint of the present invention is an outer joint member formed by joining a thin mouse member formed by cold working and a stem member, and the mouse member opens at one end, A plurality of circumferentially extending track groove portions extending in the axial direction are provided, and a taper portion whose diameter is increased toward the opening end side is provided between adjacent track groove portions.

  The tapered portion is integrally formed by cold working as a part of the mouse member (Claim 2), and the thickness does not decrease as in the case where the chamfer portion is provided by removal processing or the like. Can be prevented. Further, the size of the tapered portion is not limited by the thickness of the mouse member, and interference with the shaft can be sufficiently suppressed.

  Further, by forming a groove running in the circumferential direction for fixing the boot on the outer peripheral surface of the track groove portion (Claim 3), one end of the boot is securely fixed to the mouse member by the groove and the tapered portion. And high sealing performance can be obtained. The groove on the outer peripheral surface of the track groove portion can be formed by removal processing such as post-turning in which the mouse member is formed by cold working.

  ADVANTAGE OF THE INVENTION According to this invention, the formability in cold work, manufacturing cost reduction, and functional improvement can be aimed at, and the constant velocity universal joint with the outstanding performance can be provided in light weight, a compact, low cost.

  First, the embodiment of the present invention will be described by taking as an example the case where it is applied to the tripod type constant velocity universal joint shown in FIG.

  The tripod type constant velocity universal joint includes an outer joint member 1 connected to a drive shaft or a driven shaft, and a tripod member 3 connected to a shaft 2 serving as a driven shaft or a drive shaft. Here, the outer joint member 1 has a bottomed cylindrical shape or a cup shape, and has a track groove portion 6 that extends in the axial direction at a position of the inner circumference in the three-divided position (see FIGS. 2 and 3). The tripod member 3 has three legs protruding in the radial direction from the circumferentially divided position. A ring 5 is rotatably attached to each leg via a needle roller 4. The tripod member 3 is inserted into the outer joint member 1, and the ring 5 is engaged with the track groove portion 6 of the outer joint member 1 so as to be able to roll freely, thereby rotating torque between the outer joint member 1 and the tripod member 3. Can be transmitted.

  The outer joint member 1 includes a mouse member 1a and a stem member 1b. The mouse member 1a is formed into a cup shape by continuous press processing from a plate material, and is integrally joined to a stem member 1b manufactured as a separate body. Grooves 7 running in the circumferential direction are formed on the outer peripheral surface of the track groove 6 on the opening end side of the mouse member 1a. A tapered portion 8 is formed between adjacent track groove portions 6.

  As shown in FIGS. 2 and 3, the mouse member 1a formed by press working has a substantially uniform cross-sectional shape as shown in FIGS. In press working, materials with lower carbon content are easier to process, so low carbon steel for carburizing and quenching is often used, but high carbon steel for induction hardening is used. Also good. The mouse member 1a is formed into a required cup shape through several steps of deep drawing, ironing, punching, and the like from a disk-shaped material in press working. Further, after a forming process such as turning, a hardened layer is provided on the entire surface by carburizing and quenching, and then joined to the stem member 1b.

  An example of a method for joining the mouse member 1a and the stem member 1b is as follows. As shown in FIG. 10, the mouse member 1a is formed into a cup shape by pressing a pipe material or a bottomed cylindrical material made of a thin steel plate. In the mouse member 1a, a plurality of track grooves 6 are formed on the inner peripheral surface, and as a result, the cross section has a flower crown shape (see FIG. 11). In the center of the bottom of the mouse member 1a, a hole 40 is provided by stamping. A polygonal surface as shown in FIG. 11 (A) or a serration groove as shown in FIG. 11 (B) is formed on the inner peripheral surface of the hole 40. In either case, surface hardening such as carburizing and induction hardening is performed. Processing has been applied.

  The stem member 1b to be joined to the mouse member 1a has a serration portion formed on the outer peripheral surface of one end portion, a large diameter portion 1c formed on the other end portion, and a mouse member 1a at the tip of the large diameter portion 1c. A protrusion 1d that fits into the hole 40 is formed. This protrusion 1d is a raw material, and the surface is not cured. The outer diameter is set slightly larger than the inscribed circle diameter of the hole 40. A circumferential groove 1e is formed in a step portion between the large diameter portion 1c and the protruding portion 1d, and an O-ring or other sealing member 42 is attached to the circumferential groove 1e.

  Then, as shown in FIG. 10A, after the protruding portion 1d of the stem member 1b is press-fitted into the hole 40 of the mouse member 1a, the tip of the protruding portion 1d protruding inside the mouse member 1a is caulked by the caulking tool 46. Strike in the direction. By doing so, the end portion of the projecting portion 1d is caulked as shown by reference numeral 44 in FIG. 10B to join the mouse member 1a and the stem member 1b. In such a joined state, the polygonal surface or serration groove provided on the inner peripheral surface of the hole 40 is transferred to the projecting portion 1d to prevent the mouse member 1a and the stem member 1b from rotating, and the axial direction In this case, the backlash of the fitting portion is killed by the crimping portion 44, and the mouse member 1a and the stem member 1b rotate together. The caulking of the protruding portion 1d of the stem member 1b also has an effect of correcting the deformation of the bottom of the mouse member 1a caused by press fitting.

  12A and 12B show another joint structure between the mouse member 1a and the stem member 1b. In this case, the stem member 1b is formed to have a slightly smaller diameter than the hole 40 of the mouse member 1a, including the serration portion at the tip, and the other end of the stem member 1b has a slightly larger diameter than the inner diameter of the hole 40. A joining portion 1c is formed, and a retaining collar 1f is formed at the tip thereof. The hole 40 of the mouse member 1a has a polygonal surface or serration groove similar to that shown in FIG. 11 described above, and is subjected to a surface hardening treatment. The stem member 1b is inserted into the hole 40 from the inside of the mouse member 1a as indicated by an arrow in FIG. 12A, and the fitting portion 1c is fitted into the die 50 as shown in FIG. 12B. Together with the caulking tool 46, the stem member 1b is hit and caulked as indicated by reference numeral 48. The polygonal surface or serration groove of the hole 40 is transferred to the fitting portion 1c.

  Next, as shown in FIG. 4, the tripod constant velocity universal joint shown in FIG. 1 is used with a boot 9 for sealing the inside of the joint. The boot 9 has one open end attached to the open end of the mouse member 1 a and the other open end attached to the outer diameter portion of the shaft 2, and fastened by the fixing bands 13 and 14, respectively. The boot 9 has a bellows-like structure between the large end side mounting portions 10 and 11 and the small end side mounting portion 12 in order to allow variation in the angular displacement θ and the axial displacement X of the shaft 2 with respect to the outer joint member 1. It is manufactured by injection molding or the like using a rubber material having excellent bending durability. The large-end-side mounting portions 10 and 11 that engage with the outer peripheral surface of the opening end portion of the mouse member 1a are formed in an inner peripheral shape that is in close contact with the circumference of the circumferential groove 7 and the taper portion 8, respectively.

  As shown in FIG. 4, when the angular displacement θ of the shaft 2 with respect to the outer joint member 1 is large, the tapered portion 8 formed at the opening end of the mouse member 1 a and the opening of the mouse member 1 It serves to prevent interference with the edge. Thereby, a larger movable range is obtained and it can be set as the constant velocity universal joint applicable to a wide use.

  FIG. 5 shows a tripod constant velocity universal joint provided with a mouse member 15a as a comparative example. The mouth member 15a does not have a tapered portion at the opening end, and the chamfer 16 is provided on the inner peripheral surface of the small inner diameter portion 18 between adjacent track groove portions by removal processing such as turning after press processing. . As shown in the drawing, the opening end side of the chamfer 16 is thin, so that it is difficult to enlarge the chamfer 16 due to the problem of the strength reduction of the mouse member 15a. As a result, interference with the shaft 2 cannot be sufficiently suppressed as compared with the mouse member 1a having the tapered portion 8.

  Further, the taper portion 8 of the mouse member 1a is integrally formed in the pressing process, but the opening end portion in the deep drawing process and the ironing process is compared with the opening end shape of the mouse member 15a that does not have the taper part 8. The amount of strain can be suppressed, and as a result, cracking hardly occurs and molding becomes easy.

  On the other hand, regarding the engagement of the boots 9 and 19 with the open ends of the mouse members 1a and 15a, the engagement state of the boot large end side mounting portions 10 and 20 with respect to the circumferential grooves 7 and 17 is the same. The engagement state of the boot large end side attachment portion 11 with respect to the tapered portion 8 of 1a has a stronger axial holding force than the engagement state of the boot large end side attachment portion 21 with respect to the straight portion 18 of the mouse member 15a. In the usage state of the joint, the boot large end side attachment portion 11 is not easily displaced in the axial direction with respect to the mouse member 1a. Therefore, the mouth member 1a having the tapered portion 8 and the boot 9 can obtain higher sealing performance.

  FIG. 6 shows a mouse member 22a having a structure in which no circumferential groove (7: see FIG. 1) is provided on the outer peripheral surface of the track groove 23 portion. As described above, in the embodiment of FIG. 1, the large-end-side mounting portion 10 of the boot 9 is not easily displaced in the axial direction with respect to the mouse member 1 a in the usage state of the joint. On the other hand, the mouse member 22a of FIG. 6 is not provided with a circumferential groove, so that the large-end-side mounting portion 26 of the boot 25 is easily displaced with respect to the mouse member 22a, and the sealing performance is poor. Nevertheless, since the taper portion 24 that greatly expands toward the opening end and the boot large end side mounting portion 27 are engaged, this prevents the boot large end side mounting portion 26 from being displaced. Can be expected. On the other hand, the mouse member 22a in the embodiment of FIG. 6 does not have a circumferential groove on the outer peripheral surface of the track groove 23 portion, so there is no thin portion near the opening end of the mouse member, and in the embodiment of FIG. A strength higher than that of the mouse member 1a is obtained. Therefore, it is possible to adopt the structure of the mouse member 22a that does not have the circumferential groove according to the use condition of the joint.

  7 to 9 show an embodiment applied to a Barfield type constant velocity universal joint. As shown in the drawing, the track groove portions 29 and the taper portions 31 appear alternately in the circumferential direction at the opening end portion of the mouse member 28a. Here too, the tapered portion 31 is located between the adjacent track groove portions 29 and has a diameter increasing toward the opening end side of the mouse member 28a. A circumferential groove 30 is provided on the outer peripheral surface of the track groove portion 29. This embodiment, like the above-described tripod type constant velocity universal joint, is easy to be formed by cold working, suppresses a decrease in strength of the mouse member 28a, secures a movable range of the joint, and boots (illustrated). (Omitted) sealability can be kept good. 8 and 9 illustrate the case where the six track groove portions 29 are provided in the mouse member 28a, but the number of the track groove portions 29 is not limited to six and may be five or eight. Further, a structure in which the circumferential groove 30 is not provided on the outer peripheral surface of the track groove portion 29 can be employed in accordance with the use condition of the joint, as in the embodiment of FIG.

  Although the embodiments of the present invention have been described above, the constant velocity universal joint of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. Of course.

It is a longitudinal cross-sectional view of the tripod type constant velocity universal joint which shows embodiment of invention. It is a side view of the coupling of FIG. FIG. 3 is a sectional view taken along line III-III in FIG. 1. It is a longitudinal cross-sectional view of the joint of FIG. 1 in a state where the operating angle is taken. It is a longitudinal cross-sectional view of the joint similar to FIG. 4 which shows a comparative example. It is a longitudinal cross-sectional view of the coupling similar to FIG. 4 which shows another embodiment. It is a longitudinal cross-sectional view of the Barfield type constant velocity universal joint which shows another embodiment, Comprising: It corresponds to the VII-VII cross section of FIG. It is a side view of the coupling of FIG. It is IX-IX sectional drawing of FIG. It is a longitudinal cross-sectional view for demonstrating the method to join a mouse member and a stem member, Comprising: A shows before caulking and B shows after caulking. A and B are side views of the mouse member. It is a longitudinal cross-sectional view for demonstrating another method of joining a mouse member and a stem member, Comprising: A shows before caulking and B shows after caulking.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer joint member 1a, 15a, 22a, 28a Mouse member 1b Stem member 2 Shaft 3 Tripod member 4 Needle roller 5 Ring 6, 23, 29 Track groove part 7, 17, 30 Circumferential groove 8, 24, 31 Tapered part 9 , 19, 25 Boots

Claims (3)

  An outer joint member formed by joining a thin mouse member formed by cold working and a stem member, wherein the mouse member opens at one end, and a plurality of tracks extending in the axial direction are arranged in the circumferential direction. An outer joint member of a constant velocity universal joint, characterized in that it has a groove portion, and a tapered portion whose diameter is enlarged toward the opening end side is provided between adjacent track groove portions.   The outer joint member of a constant velocity universal joint according to claim 1, wherein the tapered portion is integrally formed by cold working as a part of the mouse member.   The outer joint member of the constant velocity universal joint according to claim 2, wherein a groove running in a circumferential direction for fixing a boot is formed on an outer peripheral surface of the track groove portion.

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